Wiping contact reed switch

ABSTRACT

A reed switch containing two reeds at least one of which is controlled by a means for producing a magnetic field. Each reed or beam is twisted along a longitudinal axis such that during operation the means for creating a magnetic field is disposed perpendicular to one of the resulting surfaces and pulls one reed into physical contact with the other in such a direction that the contact surfaces are flush. A wiping action follows between the faces of the contacting surfaces in a direction parallel to the planes of the contacting surfaces due to a component of motion in the direction of the minimum flexure axis of the moving beam.

United States Patent Eaton, deceased June 20, 1972 [54] WIPING CONTACTREED SWITCH [2 l Appl. No.2 29,156

[52] US. Cl. ..335/l54 FOREIGN PATENTS OR APPLICATIONS 1,347,244 8/1964France...'. ..335/l 51 Primary Examiner-Harold Broome AssistantEmminer-R. N. Envall. .Ir. Attorney-A. T. Stratton and C. L. McHaleABSTRACT A reed switch containing two reeds at least one of which iscontrolled by a means for producing a magnetic field. Each reed or beamis twisted along a longitudinal axis such that during operation themeans for creating a magnetic field is disposed perpendicular to one ofthe resulting surfaces and pulls one reed into physical contact with theother in such a direction that the contact surfaces are flush. A wipingaction follows between the faces of the contacting surfaces in adirection parallel to the planes of the contacting surfaces due to acomponent of motion in the direction of the minimum flexure axis of themoving beam.

9 Claims, 7 Drawing Figures WIPING CONTACT REED swrrcn BACKGROUND OF THEINVENTION Reed switches or telephone relay switches as they aresometimes known are usually quite small and encased in an envelope madeof glass or some suitable electrically insulating material. The mainreason for encasing the reeds is to keep dirt or detrimentalenvironmental substances away from the contacting surfaces of the reedswitch since they are so small that even the smallest bits of materialcan interfere with the switching action. In the past, reed switches werenot constructed with a concern for the phenomena of wiping to removeparticulate matter, in which the surfaces of the contacting points orbutts are rubbed tangentially against each other to remove any dirt orgrease which may be present. It was generally thought that theprotection of the envelope was sufficient to keep dust and otherparticles away from the contacts such that the switch could functionmany times without fouling. However, it has been found desirable toextend a reed switch's life by having a built-in wiping action. Thismeans that a switch built to operate a predetermined relatively largenumber of times can be made to operate even a greater number of times.

Other types of switches such as knife switches have employed wipingactions in which the movement of one contact against the other has beenused to remove grease, dirt, etc. from the contacting surfaces. Butbecause of their small size and the necessity for a relatively low cost,it has been impractical in the past to try to do this with a reedswitch.

SUMMARY OF THE INVENTION In accordance with the invention, a typicalreed switch is constructed. to provide a wiping action. Generally thereed switch is sealed within an electrically insulating or glass case toprevent dust and associated particles from building up on the surface ofthe contacting points. The reeds or beams of the disclosed reed switchact as conductors of electricity and respond to applied magnetic fieldsby moving to open and close the switch. The associated electromagnet ismounted external to the envelope of the switch. At least one reed orbeam, because of inherent flexibility, acts like a cantilever member inthe presence of the magnetic field applied and moves toward the otherreed or away from it depending on the direction of the magnetic field.The reeds are connected through the envelope to outside terminals sothat external circuitry can be connected and disconnected by the actionof the opening and closing reeds or beams.

In the present invention, the problems of small size and economics arejointly solved by twisting at least one beam of the reed switch andorienting the controlling magnet such that the lines of magnetic fluxare generally perpendicular to one flat surface of the twisted beam. Thetwist is made with respect to the contacting surface of the moving reedwhich remains parallel to the contacting surface of the other reed. Asthe magnetic force is applied, the part of the beam which is orientedperpendicularly to the direction of magnetic flux moves in the directionof the flux causing one contact surface to move toward the othercontacting surface but on an angle with respect to it. The result isthat one flat surface of the twisted beam does not contact the otherflat surface in a perpendicular approach as with most types of reedswitches but slides into it in an angular yet parallel approach. Thiscan be likened to the way an aircraft approaches a runway duringlanding. In general, the attitude of the aircraft is oriented parallelto the runway though approaching it on a descending angle. This occursbecause the rectangularly shaped beam has an axis of maximum flexurewhich allows the broadest side of the beam to bend or flex more easilythan along its narrow side because of the inherent structural propertiesof the rectangular cross-sectional shape of the beam. It is for thisreason that the broad or wide surface of at least one beam is orientedperpendicular to the lines of magnetic flux and as the magnetic force isapplied, it easily flexes in that direction and causes contact to bemade by the angularly displaced flat surfaces as previously described.However, once contact is made, the beam can no longer easily bend in thedirection of the magnetic flux although it still has the propensity ortendency to move in that direction under the influence of the appliedmagnetic field. The only degree of freedom of motion remaining is in thedirection of the narrow surface corresponding to the axis of minimumflexure. Motion in this direction causes the contacts to move or slidetangentially with respect to each other until a point is reached wherethe limit in elasticity along the minimum flexure axis prevents anyfurther movement in that direction thus causing the beam to stop orcease moving in any direction regardless of the presence of the magneticfield and at that instant, the contact or closing cycle is completed.During an'opening operation, when the magnetic field or source ofmagnetic flux is removed or deenergized, the switch contacts are openedin a manner which is exactly the reverse of the closing operation justdescribed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a view of one example ofa prior art reed switch;

FIG. 2 shows a partially cut-away side view of a reed switchillustrating a principal embodiment of the invention;

FIG. 3 shows a sectional view of the invention shown in FIG. 2 takenalong line III-III in FIG. 2 prior to the start of the closing cyclewhen the switch is open;

FIG. 4 is a sectional view of the invention, similar to FIG. 3, at atime later in the closing cycle than that shown in FIG. 3;

FIG. 5 is a similar sectional view to those shown in FIGS. 3 and 4 atthe end of the closing cycle;

FIG. 6 shows another embodiment of the invention; and

FIG. 7 is a sectional view of the embodiment shown in FIG. 6 shown alongline VII-VII in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingsand FIG. 1 in particular, there is shown a prior art reed switch 8, inwhich a casing or envelope 10 made of any suitable dielectric orinsulating material, such as glass, is used to enclose two reeds orbeams 12 and 14. Beams l2 and 14 are flexible and each beam includesthree separately identifiable sections or portions which are associatedwith it. Reed 12 has section 12a which is the anchoring end portion ofthe reed' 12 and is attached to the glass envelope 10 through an opening16L in the glass envelope or enclosure 10. It may be attached by a glueor resin or merely by a pressure fit. Section 12a acts as both an anchorand a terminal. Section 12m is the main body of the reed or beam and iscantilevered outwardly from anchor section 12a and is flexible orspringy, that is it can bend easily toward either the top or bottom ofthe glass envelope 10. Beam or flexible member 14 is constructed similarto beam 12. That is anchor or terminal section 14a is attached toenvelope 10 at opening 16R and the main body of the beam 14m may alsobend or flex similarly to beam 12. It will be noted that sections orportions and are the contacting points for this switch and respectivelythey form the third identifiable sections of each beam. Under theinfluence of a magnetic field perpendicularly oriented to sections 12mor 14m, section or contact 12c will move toward section 140, or sectionor contact 14c will move toward contact 12c. Upon physical contact ofthe contacts 12c and 140, electrical continuity or a current carryingpath will then exist between points 12a and 14a and of course anycircuits which are attached to the associated terminals.

Referring now to FIG. 2, the reed switch 8' shown includes an ovaloidenvelope 10' which is similar to the envelope 10 of switch 8 shown inFIG. 1. Envelope 10' may be substantially evacuated or filled with aninert fluid, such as argon to prevent oxidation. Openings 16L and 16R inthe envelope serve the same purpose as openings 16L and 16R of envelope10 shown in FIG. 1. In this embodiment of the invention, the switch 8'includes two beams 18 and 20. Beam 18 is similar to beam 14 shown inFIG. 1 except that it is relatively shorter. It has an anchoring orterminal end or portion 18a which projects or extends through an opening16R in the envelope 10 along a longitudinal axis 21R of the switch 8'.It also has a contact point or section 18c similar to contact point 140of the switch shown in FIG. I. Contact point 18c may be more highlyconductive than the rest of beam 18 to reduce contact resistance and maybe smoothed to reduce friction. It will be noted, however, that mainbody portion 18m is much shorter than the main body portion 14m of theswitch shown in FIG. I and it does not possess the inherent flexibilityor springiness of main body 14m. Beam 18 is therefore relatively rigidand any flexibility in switch 8' is provided in beam or flexible member20. Flexible or resilient member 20 is similar to flexible member 12 inFIG. 1 in that it has an anchoring end or terminal 200 anchored orscrewed in a convenient manner to envelope 10' as it passes through theopening 16L. It also has a main longitudinal axis 21 and a secondlongitudinal axis, 21L in the vicinity of opening 16L, which is thelongitudinal axis of anchor 20a. It has a contact point 200 at theopposite end of beam 20 away from the terminal end 200 which is disposedto engage contact point 18c and complete a circuit which extends betweenthe terminal sections 180 and 20a. One difierence between the reeds orbeams 12 and 20 is the extended or relatively greater length of beam 20to compensate for the shortening of the associated beam 18. But the mostsignificant structural difference between the beams 12 and 20 is thetwist in beam 20 indicated at 19R in FIG. 2 about longitudinal axis 21.The twist causes the main body 20m of beam 20 to be angularly displacedfrom the region or portion 200 about the longitudinal axis 21 of beam20. This twist in beam 20 defines two angularly displaced planes, one ofwhich is defined by the main body portion 20m of beam or lever 20 andthe other of which is defined by the contacting surface or region 20c.

For a better understanding of the operation of the main embodiment ofthe invention, reference may be had to FIG. 3 which is a sectional viewof the switch shown in FIG. 2. It will be noted that in this embodiment,enclosure or envelope 10' is generally cylindrical and circular incross-section as illustrated although different cross-sectional shapesmay be employed in other applications. Any enclosing surface capable ofallowing magnetic flux to pass through while keeping dirt and smallparticles out is acceptable regardless of material or shape providedthat the space inside the enclosure is sufficient to permit the motionsnecessary within it during the operation of the switch 8'. As can beseen in FIGS. 2 and 3, an electromagnet 22 is provided and its face isoriented or disposed parallel to the plane of the main body section 20mthus creating magnetic flux lines 23 which flow in generally parallelpath through envelope l perpendicularly through or with respect tosurface 20m. As magnetic field 23 is first applied to the switch 8', atthe instant after electromagnet 22 has been energized so as to start toclose relay 8', a force indicated by directional arrow or vector 24,having components 28 and 26 act on the beam 20. It will be noted for thesake of simplicity that this force 24 is shown to act on the geometriccenter of beam 20 or on axis 21. Upon the first application of power toelectromagnetic 22, and the subsequent creation of the magnetic field23, beam 20 begins to move in the direction of force indicated by arrowor vector 24. The force indicated by arrow 24 can be resolved into twocomponents at right angles to each other; one is a force component 26which acts to bring flat contact surface 20c closer to flat contactsurface 180. The other is a force component 28 which acts to movecontact surface 20c tangentially with respect to contact surface 180.The net effect of this motion in the initial application of magneticforce is to move beam 20 along an oblique angle of direction withrespect to beam 18 such that surface of contact 200 slides into orangularly approaches surface 18c in the general direction of arrow 24.

Referring now to FIG. 4, it will be noted that although the magneticforce 23 still exists, beam 20 has completed its movement in thedirection of arrow 24, and engages or is butted flush against surface18c at the contact surface 200. Surface or main part 20m of beam 20 hasnot been further distorted or twisted with respect to 20 by theapplication of the magnetic field and it is not the purpose of thisinvention to deliberately change the angle theta (0) of section ortwisted region 19R as shown in FIG. 4 at any time during the operationof the invention although that may occur to a slight degree. Contactsurface 20c has laterally been displaced a distance d with respect tocontact surface when the switch 8' is closed as shown in FIG. 4.

Referring now to FIG. 5, the main advantage of the disclosed switchstructure is illustrated. Even though the beam 20 has made initialcontact as shown in FIG. 4, the force resulting from magnetic flux lines23 has not diminished, and beam 20 still has a tendency to move in thedirection of force component 24' because of the acceleration imposedupon it by the action of the magnetic flux 23. But it is restrained frommoving in direction 24' by the stopping action of beam 18. The motioncorresponding to force 24 can only be accomplished if the flexible beamor member 20 is caused to slide sideways or move laterally in adirection 28'. It will be noted that in order to do this, there must bea component of force in the direction 30 acting on beam 20. The forcecomponent 30 is along the minimum flexure axis 31 of beam 20 in section20m. It will be noted by examining the two superimposed views of beam 20shown in FIG. 5, that the beam 20 has moved an additional distance dfrom the position shown in FIG. 4. This distance is measuredtangentially along surface 18c. The movement of beam 20 through thedistance d causes the wiping action that is necessary to remove anyresidue on either surface 200 or 18c or both. The main direction ofmovement of beam 20 during this wiping action is direction 28' becauseof the restriction of movement in direction 24' due to the presence ofthe blocking or stopping surface 18c. It is not to say that beam 20 doesnot move at all in direction 24 since beam 18 has some slight residualspringiness. But the motion in direction 24' is severely limited whencompared to the kind of motion that was shown in FIG. 3 and in fact anew component of motion 30 is introduced into the overall motion of thebeam 20.

FIGS. 3, 4 and 5 considered together show that contact surfaces 20c and180 engage or meet due to the motion of contact surface 20c in anangular path as it approaches surface 18c and upon engagement, contactsurface 20c slides or moves in a direction 28' causing wiping of contactsurfaces 200 and 18c. This wiping or removal of dirt and grease or anyother foreign matter is one of the main advantages of the disclosed reedswitch structure since it provides for better physical contact and thusthe electrical resistance between the engaged surfaces 20c and surfaces180 is minimized during the life of the switch 8.

FIG. 6 shows another embodiment of the invention in a switch 9 in whichtwo beams or reeds 20' and 32 are displaced within envelope or enclosure10''. The switch structure 9, differs from the switch structure 8 shownin FIGS. 2 through 5 in that beam 20' shown in FIG. 6 is shorter thanbeam 20 shown in FIG. 2 and that beam or reed 32 shown in FIG. 6 isgenerally longer and otherwise is structurally different from beam 18shown in FIG. 2. The most significant difference between beam 32 andbeam 18 is that beam 32 more closely resembles beam 20. In other words,the beam 32 has inherent flexibility of its own. Consequently both ofthe beams 32 and 20 act in a similar manner during the operation of theswitch 9. First, beam 20' is anchored in the vicinity of end 20a toglass envelope 10" at opening or hole 16L". Second, there is a mainsection or portion 20m which is attached to anchoring end 20a. Also, inthe region 19R, beam 20' is twisted such that a new surface or planeoffset by a predetermined angle 0 is formed, as indicated at 20c.Portion or section 200' is the contacting surface for beam 20'. In alike manner, beam 32 is attached in the vicinity of anchoring end orterminal portion 32a to envelope 10" at hole or opening 16R". Beam 32also has a main body portion 32m, similar to main section or portion 20mof beam. There is a twist 32L in beam or reed 32 forming a new plane32c. Preferably, this causes surfaces 32c and 200' to be alignedsubstantially parallel to each other for subsequent flush physicalcontact or engagement upon closure of reed switch 9. There are twoelectromagnets or magnetic devices associated with reed switch 9, one onthe left associated with beam 20 which is the electromagnet 22 and oneon the right associated with beam 32 which is electromagnet 25. Uponenergization of the magnets 22 and 25, beam 20' is pulled toward beam32', while beam 32' is pulled toward beam 20 causing a quicker or fasterclosure of parallel contact surfaces 200' and 32c and for greater wipingaction between said contact surfaces.

Referring now to FIG. 7, a sectional view of the reed switch of FIG. 6is shown. Electromagnets 22' and 25 are shown with their respectivemagnetic fields 23' and 27. Electromagnet 25 is aligned substantiallyperpendicular to main body or section 32m of beam 32 and causes beam 32to move in the general direction 48. This motion has a component 52which is perpendicular to contacting surface 32c and a component 50which is parallel to the surface 32c. Concurrently, magnet 22' isexerting a force on beam 20 causing main body or section 20m to move ina direction 44 with resulting component of force 42 which isperpendicular to surface 20c and a component of force 46 which isparallel to the surface 20c. The overall effect of the electromagnets 22and 25, is to move surfaces 32c and 20: toward each other in a parallelangled approach until'contact is made. When contact is made, the wipingefiect or action mentioned with respect to the switch 8' of FIG. 5results except that both contacting members 32c and 200' have a tendencyto slide or wipe tangentially with respect to each other. Beam 20' movesor is actuated to the left in a general direction 46, while beam 32moves or is actuated to the right in direction 50. This creates a doubletangential wiping motion which gives twice the wiping effect or actionthan if only one relatively movable beam were used as in the switch ofFIGS. 2 through 5.

It is to be understood that with regard to either of the embodiments ofthe invention, the envelope indicated for example by 10 of FIG. 1 or10'' in FIG. 6 can be of any general shape and of any kind of dielectricmaterial and need not be evacuated. Its purpose is to protect thecontacting surfaces from breakage during handling, detrimentalenvironment, dust or dirt. It should also be realized that the angletheta (9) may be varied within a predetermined range in accordance withthe invention. If the angle selected is very large, (such as approaching90) there will be substantially no engagement between surfaces 200 and180 as shown in FIGS. 2 through 5 and if the angle selected is toosmall, such as approaching zero degrees, the switch operation willprovide the advantages previously mentioned to a much lesser degree. Thecurrent carrying capabilities of the different embodiments of theinvention described are limited by the surface remaining after wipingaction has been completed. The electromagnets, such as 22 shown in FIG.2 or 22' and 25 as shown in FIG. 6 may be of any standard type such asthose generally associated with the reed switches. It should also beunderstood that general irregularities in contact surfaces have atendency to cause friction which will retard the wiping motion asdescribed in the previous embodiments of the invention. This, however,is not critical since, although contact friction cannot be completelyeliminated it will, after a gradual wearing or seating of the contactsurfaces, be reduced to a minimum. It should finally be noted that evenwith respect to beam 18 in FIG. 2 which is substantially inflexible,there is a slight flexibility in the direction of force 24, as shown inFIG. 3 and this is conductive to better wiping action as it allows beam20 to move slightly more in direction 24 as shown in FIG. 5 which is ofcourse more than would be allowed or pennitted had beam 180 beenperfectly rigid.

The apparatus embodying the teachings of this invention have severaladvantages. For example, the disclosed switch structures are easilyconstructed and can be used to create a relatively simple contact wipingreed switch without the need for elaborate machining or mechanicaloperations. The twisting of the beam creates the angle theta (0) betweenthe different portions of the beam structures which provides the contactwiping advantages in the operations of the switch structure previouslydescribed.

What is claimed is:

l. A reed switch comprising a plurality of elongated electricallyconducting flexible members mounted within an elongated protectingenvelope, said members each having an anchoring end, a contacting endand an intermediate main body, said anchoring ends being axially spacedand secured to the opposite ends of said protecting envelope andextending through and into saidprotecting envelope, a portion of eachsaid anchoring end projecting outside of said protecting envelope todefine an electrical terminal, said contacting ends being disposed inproximity to each other and to axially overlap, means disposed adjacentto said envelope for providing separate magnetic fields to generallyinteract with said main body only of one said members and to generallyinteract with no other member, said main bodies of said flexible membersbeing capable of motion under the influence of said magnetic field, saidmain body for each member having a minimum flexure axis and a maximumflexure axis displaced from said minimum flexure axis and having atendency to move in a first direction corresponding to the direction ofsaid maximum flexure axis when said magnetic field is applied thereto,whereby said anchoring end remains generally stationary while said mainbody and said contacting end move in reaction to the application of saidmagnetic field, each said main body having a separate longitudinal axisperpendicular to said maximum and said minimum flexure axes, a portionof at least one of said members being displaced angularly along saidlongitudinal axis by a twist in said member between said main body andsaid contacting end, said main body of at least the lastmentioned membermoving in said first direction when said separate magnetic field isapplied to the main body thereof until said contacting ends of saidmembers engage, said contacting ends being disposed substantiallyparallel to each other upon engagement, generally thereafter at leastone of said members moving in a second direction whilev under theinfluence of said magnetic field thus causing a component of movement insaid at least one of said members generally in the direction of the saidminimum flexure axis only, said subsequent movement in said seconddirection causing at least one of said engaged contacting ends to movetangentially with respect to the other to thereby cause a wiping actionbetween said contacting ends, the friction between said contacting endsduring engagement being generally of a value which allows at least oneof said contacting ends to move tangentially in said second direction,whereby the contacting end of another of said members acts as a stoppingsurface to substantially restrict the movement of said at lest one ofsaid contacting ends to substantially only said second direction.

2. A reed switch comprising two elongated electrically conductingflexible members mounted within an elongated protecting envelope, saidmembers each having an anchoring end, a contacting end and anintermediate main body, said anchoring ends being axially spaced andsecured to the opposite ends of said protecting envelope and extendingthrough and into said protecting envelope, a portion of each of saidanchoring ends projecting outside of said protecting envelope to definea terminal, said contacting ends being disposed in proximity to eachother and to axially overlap, said main bodies of said flexible membersbeing capable of motion toward one another, a pair of means forproducing two magnetic fields, one for each member with the magneticfield for each member substantially intersecting only the associatedmember, said magnetic field associated with each member generallyinteracting with said main body only of the associated member, said mainbody of each member having a minimum flexure axis and a maximum flexureaxis displaced ninety degrees from said minimum flexure axis and havinga tendency to move in a first direction corresponding to the directionof said maximum flexure axis in the respective main body when its saidmagnetic field is applied thereto, whereby said anchoring end remainsgenerally stationary while said main body and said contacting end pivotabout said anchoring end, each said main body having a longitudinal axisperpendicular to said maximum and minimum axes, said main body of eachsaid members being displaced angularly with respect to said longitudinalaxis by a twist in said member between said main body and saidcontacting end, said main body of each member moving in said firstdirection when said magnetic fields are applied thereto until saidcontacting ends of said members engage, said contacting ends beingdisposed substantially parallel to each other upon engagement, at leastone of said members thereafter moving in a second direction, causingmovement of said at least one of said members generally in the directionof the minimum flexure axis, while under the influence of said separatemagnetic field, said movement in said second direction causing said atleast one of said engaged contacting ends to move tangentially withrespect to the other to thereby cause a wiping action between saidcontacting ends, said protecting envelope is hollow ovaloid in shape andis formed from an electrically insulating material, said envelopeextending along an additional longitudinal axis, said anchoring endsbeing disposed generally symmetrically with respect to said additionallongitudinal axis, said main body and contacting ends of both saidmembers being comprised of elongated rectangular beams, said beams ofsaid main bodies being joined to said respective anchoring ends, saidmain bodies of said members lying respectively in a first pair ofparallel planes, said contacting ends of said members each lyingrespectively in a second pair of parallel planes angularly displacedfrom said first pair of parallel planes due to said twist in each saidmember, said parallel contacting ends being adapted to overlap uponengagement along said longitudinal axis of said envelope, said magneticfields being axially spaced and applied on opposite sides of saidenvelope and being oppositely oriented generally perpendicularly withrespect to said associated set of parallel planes of said main bodies toactuate said members toward and to engage one another in a firstdirection of motion in each case and to move thereafter in each case insubstantially only a second direction.

3. The combination as claimed in claim 1, wherein said plurality ofmembers comprises two members, a first of said members is relativelyless flexible and longitudinally shorter than the other of said members,the other of said members being relatively longer and more flexible dueto its greater length, said protecting envelope being hollow ovaloid inshape and formed from an electrically insulating material, said envelopeextending along an additional longitudinal axis, said anchoring endsbeing disposed generally symmetrically with respect to said additionallongitudinal axis, said main body and said contacting ends of both saidmembers being comprised of rectangular beams, said beams of said mainbodies being joined to said respective anchoring ends, only said othermember having said twist between its said main body and said contactingend such that said contacting ends of both said members are disposed ingenerally parallel planes before motion while the main bodies of saidmembers are not, said parallel contacting ends being adapted to overlapupon engagement along the said longitudinal axis of said envelope, onlysaid other of said members being placed upon the influence of saidmagnetic field for inducing movement and upon contact only said othermember moving in the said second direction to wipe said first member.

4. The combination as claimed in claim 2, in which at least one of saidpair of means for providing said magnetic field comprises anelectromagnetic adapted to be energized from a controllable source ofelectrical energy.

5. The combination as in claim 3, wherein said means for providing saidmagnetic field comprises an electromagnet adapted to be energized by asource of controllable electrical ener 6. f he combination as claimed inclaim 1 wherein said protecting envelope is initially substantiallyevacuated of atmospheric material.

7. The combination as claimed in claim 1 wherein said envelope issubstantially filled with an inert fluid.

8. The combination as claimed in claim 2 wherein said protectingenvelope is initially substantially evacuated of atmospheric material.

9. The combination as claimed in claim 2 wherein said envelope issubstantially filled with an inert fluid.

I i k i

1. A reed switch comprising a plurality of elongated electricallyconducting flexible members mounted within an elongated protectingenvelope, said members each having an anchoring end, a contacting endand aN intermediate main body, said anchoring ends being axially spacedand secured to the opposite ends of said protecting envelope andextending through and into said protecting envelope, a portion of eachsaid anchoring end projecting outside of said protecting envelope todefine an electrical terminal, said contacting ends being disposed inproximity to each other and to axially overlap, means disposed adjacentto said envelope for providing separate magnetic fields to generallyinteract with said main body only of one said members and to generallyinteract with no other member, said main bodies of said flexible membersbeing capable of motion under the influence of said magnetic field, saidmain body for each member having a minimum flexure axis and a maximumflexure axis displaced 90* from said minimum flexure axis and having atendency to move in a first direction corresponding to the direction ofsaid maximum flexure axis when said magnetic field is applied thereto,whereby said anchoring end remains generally stationary while said mainbody and said contacting end move in reaction to the application of saidmagnetic field, each said main body having a separate longitudinal axisperpendicular to said maximum and said minimum flexure axes, a portionof at least one of said members being displaced angularly along saidlongitudinal axis by a twist in said member between said main body andsaid contacting end, said main body of at least the last-mentionedmember moving in said first direction when said separate magnetic fieldis applied to the main body thereof until said contacting ends of saidmembers engage, said contacting ends being disposed substantiallyparallel to each other upon engagement, generally thereafter at leastone of said members moving in a second direction while under theinfluence of said magnetic field thus causing a component of movement insaid at least one of said members generally in the direction of the saidminimum flexure axis only, said subsequent movement in said seconddirection causing at least one of said engaged contacting ends to movetangentially with respect to the other to thereby cause a wiping actionbetween said contacting ends, the friction between said contacting endsduring engagement being generally of a value which allows at least oneof said contacting ends to move tangentially in said second direction,whereby the contacting end of another of said members acts as a stoppingsurface to substantially restrict the movement of said at lest one ofsaid contacting ends to substantially only said second direction.
 2. Areed switch comprising two elongated electrically conducting flexiblemembers mounted within an elongated protecting envelope, said memberseach having an anchoring end, a contacting end and an intermediate mainbody, said anchoring ends being axially spaced and secured to theopposite ends of said protecting envelope and extending through and intosaid protecting envelope, a portion of each of said anchoring endsprojecting outside of said protecting envelope to define a terminal,said contacting ends being disposed in proximity to each other and toaxially overlap, said main bodies of said flexible members being capableof motion toward one another, a pair of means for producing two magneticfields, one for each member with the magnetic field for each membersubstantially intersecting only the associated member, said magneticfield associated with each member generally interacting with said mainbody only of the associated member, said main body of each member havinga minimum flexure axis and a maximum flexure axis displaced ninetydegrees from said minimum flexure axis and having a tendency to move ina first direction corresponding to the direction of said maximum flexureaxis in the respective main body when its said magnetic field is appliedthereto, whereby said anchoring end remains generally stationary whilesaid main body and said contacting end pivot about said anchoring end,each said main boDy having a longitudinal axis perpendicular to saidmaximum and minimum axes, said main body of each said members beingdisplaced angularly with respect to said longitudinal axis by a twist insaid member between said main body and said contacting end, said mainbody of each member moving in said first direction when said magneticfields are applied thereto until said contacting ends of said membersengage, said contacting ends being disposed substantially parallel toeach other upon engagement, at least one of said members thereaftermoving in a second direction, causing movement of said at least one ofsaid members generally in the direction of the minimum flexure axis,while under the influence of said separate magnetic field, said movementin said second direction causing said at least one of said engagedcontacting ends to move tangentially with respect to the other tothereby cause a wiping action between said contacting ends, saidprotecting envelope is hollow ovaloid in shape and is formed from anelectrically insulating material, said envelope extending along anadditional longitudinal axis, said anchoring ends being disposedgenerally symmetrically with respect to said additional longitudinalaxis, said main body and contacting ends of both said members beingcomprised of elongated rectangular beams, said beams of said main bodiesbeing joined to said respective anchoring ends, said main bodies of saidmembers lying respectively in a first pair of parallel planes, saidcontacting ends of said members each lying respectively in a second pairof parallel planes angularly displaced from said first pair of parallelplanes due to said twist in each said member, said parallel contactingends being adapted to overlap upon engagement along said longitudinalaxis of said envelope, said magnetic fields being axially spaced andapplied on opposite sides of said envelope and being oppositely orientedgenerally perpendicularly with respect to said associated set ofparallel planes of said main bodies to actuate said members toward andto engage one another in a first direction of motion in each case and tomove thereafter in each case in substantially only a second direction.3. The combination as claimed in claim 1, wherein said plurality ofmembers comprises two members, a first of said members is relativelyless flexible and longitudinally shorter than the other of said members,the other of said members being relatively longer and more flexible dueto its greater length, said protecting envelope being hollow ovaloid inshape and formed from an electrically insulating material, said envelopeextending along an additional longitudinal axis, said anchoring endsbeing disposed generally symmetrically with respect to said additionallongitudinal axis, said main body and said contacting ends of both saidmembers being comprised of rectangular beams, said beams of said mainbodies being joined to said respective anchoring ends, only said othermember having said twist between its said main body and said contactingend such that said contacting ends of both said members are disposed ingenerally parallel planes before motion while the main bodies of saidmembers are not, said parallel contacting ends being adapted to overlapupon engagement along the said longitudinal axis of said envelope, onlysaid other of said members being placed upon the influence of saidmagnetic field for inducing movement and upon contact only said othermember moving in the said second direction to wipe said first member. 4.The combination as claimed in claim 2, in which at least one of saidpair of means for providing said magnetic field comprises anelectromagnetic adapted to be energized from a controllable source ofelectrical energy.
 5. The combination as in claim 3, wherein said meansfor providing said magnetic field comprises an electromagnet adapted tobe energized by a source of controllable electrical energy.
 6. Thecombination as claimed in claim 1 wherein said protecting envelope isinitially substantially evacuated of atmospheric material.
 7. Thecombination as claimed in claim 1 wherein said envelope is substantiallyfilled with an inert fluid.
 8. The combination as claimed in claim 2wherein said protecting envelope is initially substantially evacuated ofatmospheric material.
 9. The combination as claimed in claim 2 whereinsaid envelope is substantially filled with an inert fluid.